六相整流发电机接地方式对船舶中压电力系统谐波影响

为抑制因单相接地故障而引起的船舶中压电力系统非特征谐波,以六相整流发电机为例,研究了其中性点接地方式对谐波的影响。首先,运用开关函数和对称分量法,分别得出正常运行时直流电压特征谐波以及故障下非特征谐波计算方法,再利用直流电压推导出了交流故障电流的谐波表达式。其次,分析了非故障绕组零序回路,运用功率平衡原则,得到接地电阻与非故障绕组零序电压的关系,分析出接地方式对谐波的影响。最后,通过PSCAD/EMTDC仿真平台和实验验证了所得到的结论,为船舶中压直流电力系统接地方式的选取提供了参考和依据。

Influence of grounding mode of 6-phase generator with rectifier-load on harmonics in shipboard medium voltage power system

In order to suppress the non-characteristic harmonics in shipboard medium voltage power system caused by single phase grounding fault, the influence of neutral grounding mode of the 6-phase generator with rectifier-load on the harmonics is studied. Firstly, the switching function and method of symmetrical components are used, the calculation methods of characteristic harmonics at normal situation and non-characteristic harmonics in fault situation of DC voltage are obtained respectively, then the harmonics expression of AC fault current is deduced by using DC voltage. Secondly, the zero-sequence loop in fault is analyzed, and the relationship between grounding resistance and non-characteristic harmonics of DC voltage is obtained, and the influence of grounding mode on harmonics is analyzed. Finally, the conclusions are verified by simulation software PSCAD/EMTDC and experiments. The obtained results provide a basis for the selection of grounding mode for shipboard medium voltage power system. This work is supported by National Natural Science Foundation of China (No. 51607184).